Marine propulsion apparatus



Fel 5, 1963 D. R. sTAPLEToN 3,076,427

MARINE PROPULSION APPARATUS Filed Dec. 8, 1959 2 Sheets-Sheet 1.

l 'MW Feb. 5, 1963 D. R. sTAPLEToN 3,076,427

MARINE PROPULSION APPARATUS lFiltad Dec. 8, 1959 2 Sheets-Sheet 2 5a/@alor United sat-es Patent one@ 3,076,427 Patented Feb. 5, 1963 3,076,427 MARINE PRUPULSON APPARATUS Donald R. Stapleton, RO. Box 237, Leda, Ill. Filed Dec. 8, 1959, Ser. No. 858,086 4 Claims. (Cl. 11S- 16) The present invention relates to means for driving or propelling boats or ships, and more particularly to .a marine propulsion apparatus adapted for small boats.

Among the objects of the invention is the provision of marine propulsion apparatus which provides great flexibility in operation without requiring changes in the operation of the driving means.

Another object is the provision of such apparatus achieving forward or reverse movement or neutralization of the moving force without requiring gearing, clutches, or other complicated and expensive mechanism.

Another object is the provision of a marine propulsion apparatus which provides for quick and positive reversal of the direction of movement of the boat without shock or strain being imposed upon the boat or the apparatus.

A further object of the invention is the provision of a marine propulsion apparatus which achieves a very high degree of safety, particularly for people in the water through which the boat moves, by reason of having n exposed propeller or other rotating parts.

Still another object of the invention is the provision of such an'apparatus which provides a very quick and positive steering response, particularly in forward movement.

Another object is the provision of va marine propulsion apparatus in which the developed thrust is dis-tributed over a large area of the boat hull so .as to eliminate high or concentrated stress at any particular point.

A further object is the provision of a marine propulsion apparatus which by reason of its .arrangement and location may permit the use of less bracing than is ordinarily required.

Another object is the provision of a marine propulsion apparatus which may be assembled, transported, and installed as a unit.

Another object of the invention is the provision of marine propulsion apparatus employing a turbine wheel to develop a powerful, high-speed jet which achieves a very high efficiency by reason of the turbine wheel blades having an improved shape to drive substantially all the water engaged thereby as a jet while carrying substantially no water about the axis of the wheel.

A still further object is the provision of such apparatus which allows operation of the boat in very shallow water.

Another object is the provision of a marine propulsion unit which provides for control of the speed of boat movement without requiring change in the speed of the driving means.

Another object is the provision of a marine propulsion apparatus which is not readily damaged.

Still another object of the invention is the provision of marine propulsion apparatus which may be located in the stern of a boat to provide more usable free space within the hull.

The above and other objects, and the advantages and features of the invention, will be apparent from the following description, taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a fragmentary plan view of a boat employing the marine propulsion .apparatus of the invention;

FIG. 2 is Va side elevational view of the boat and apparatus shown in FIG. l;

FIG. 3 is an enlarged vertical longitudinal section taken substantially as indicated by the line 3-3 of FIG. l;

FIG. 4 is a horizontal sectional view taken substantially .as indicated by the line 4-4 of FIG. 3;

FIG. 5 is a transverse sectional view taken substantially as indicated by the line 5-5 of FIG. 3;

FIG. 6 is a view similar to FIG. 3, but showing another embodiment of the invention;

FIG. 7 is a horizontal sectional view, Vlooking upwardly, takensubstantially as indicated by theline 7-7 of FIG. 6;

FIG. 8 is a transverse sectional view ltaken substantially as indicated by the line 3-8 of FIG. 6; and

FIG. 9 is an enlarged view of one of the turbine blades illustrating ydetails thereof.

Referring first to FIGS. 1 to 5, there is shown the -stern portion of a boat hull H, on the bottom B of which the propulsion ,apparatus of the invention is mounted. Two of these apparatus are shown in FIG. l, in a twin. or parallel arrangement, adapted to be driven by a single motor or engine E, such as an internal combustion engine, although it will be obvious that more or fewer of the apparatus may be employed if desired.

A single apparatus 'accordingrto the present invention may be provided-for mounting on the bottom ofthe boat as a unit, requiring no further assembly of its parts, or substantially as'a unit, 'requiring only a minimum assembly of additional parts after mounting, as will hereinafter appear. The apparatus as shown in FIGS. l to 5, inclusive, comprises a base Vplate 1li which has adjacent one end thereof an elongated rectangular aperture 11. The base plate is secured to the bottom B of the boat by any suitable means (not shown), or in any suitable manner, as by bolts, screws, rivets, welding, or the like. In the present instance, a weld 10 is shown as used for this purpose. The boat bottom has an aperture 12 formed therein somewhat larger than the `base plate aperture 11,l to accommodateV the mounting flanges 13 of a turbine wheel housing 14 which is of generally cylindrical form but is open in the plane of the flanges 13 for communication wi-th the aperture 11. The housing 14, as best shown in FIGS. 4 and 5, may have one side thereof closed by an integral wall 15, and the other by a removable plate 16 secured to the housing in any suitable Inanner, as by attachment to a fiange 17 of the housing by cap screws 13 or the like. The mounting flanges 13 of the housing 14 are welded, screwed, bolted, riveted, or otherwise suitably secured to the base plate 10 about the margins of the aperture 11 and within the aperture 12 in the bottom B, the flanges 13 engaging against the face of the base plate 1d which lies in engagement with the boat bottom in the mounted condition of the apparatus.

The wall 15 and plate 16 of the turbine wheel housing 14 are formed with suitable bearing bosses 19 which journal a shaft Ztl extending transversely through the housing and arranged to be driven by the engine E. It will be appreciated that in actual practice any suitable anti-friction bearings may be employed for the shaft 20. Fixed on the shaft portion within the housing 14 is a turbine wheel generallydesignated 21, in'this case shown as comprising a hollow drum type hub 22 from the circumference of which extend a plurality of equally spaced blades 23 which are of substantially rectangular form in face elevation, as will be clear from FIG. 4, and are curved in section or en'cl elevation, as will be clear particularly from FIG. 3. A more detailed explanation of the formation of the blades 23 is given hereinafter. The housing is formed to fit closely about vthe turbine wheel v21, but to allow sufficient clearances for free rotation of the wheel therein. The turbinewheel is fixed on the shaft 29 by any suitable means, exemplified in this instance by the set screws 24. The shaft 20 is so located relative to the base plate 10 upon mounting of the housing 14 thereon that'the circumference of the drum hub 22 comes just to the plane ofthe lower face ofthe base vplate 10, as readily be apparent'from FIG. 3.

will

On the bottom of the base plate there is defined a tubular structure which extends longitudinally in alignment with the aperture 11. In FIGS. l to 5, this tubular structure comprises a first tube 25 extending from a point somewhat forward of the forward end of the aperture 11 to a point appreciably to the rear of the rear end of the aperture, and a second and cross-sectionally larger tube 26 extending from a point somewhat forward of the rear end of the tube 2S to a point considerably to the rear thereof, as will be evident from FIGS. l to 4, inclusive. In the present case, the tubes 25 and 26 are provided by members of channel section having their outturned flanges secured to the bottom face of the base plate It) in any suitable manner, as by bolts or cap screws 27, as best shown in FIG. 5. As already mentioned, the forward end portion of the tube 26 extends somewhat forwardly of the rear end of the tube 25', so that it is in overlapping and surrounding relation with the rear portion of tube 25. This overlapping relation of the two tubes, together with the difference in the cross-sectional areas of the two tubes, provides passage means 27 openingr forwardly from the tube 26, as will be particularly evident from FIGS. 3 and 5. 'I' he cross-section of the tube 2S corresponds in shape and dimensions to the face elevation of the blades 23, with sufficient clearance to allow the blades to rotate freely through the aperture Il into and out of the passage defined by the tube. Both of the tubes 25 and 26 are open at both their front and rear ends.

In addition thereto, in most cases, it will be necessary or desirable to provide an additional opening 27 in each side wall of the tube 25, as clearly illustrated in FIG. 3, located just ahead of the vertical diameter of the turbine, to provide adequate entrance capacity for the incoming water. To prevent the entrance of debris, fioating objects, marine vegetation and the like into the open forward end of the tubular construction, suitable guard means (not shown) may be provided.

Upon rotation of the turbine wheel 21, the blades 23 will develop a strong stream or jet of water flowing rearwardly through the tube 25 and the second tube 26 to provide a thrust which by reaction with the hull H drives the boat forward. The turbine wheel is arranged to be driven in a counterclockwise direction as viewed in FIGS. 2 and 3 by means of a suitable driving belt D trained about pulleys 28 and 29 respectively fixed on the shaft of the engine E, and the shaft 2d. As will be clear from FiG. l, where more than one marine propulsion apparatus according to this invention is employed, they may all be driven from a single engine E by making the shaft common thereto. The shaft, belt, and pulleys may be suitably enclosed for cleanliness and safety.

The blades 23 of the turbine wheel are of a shape specifically provided to achieve the maximum efficiency in developing the driving or thrusting jet or stream, the form of the blades resulting in substantially no carryover of water from the tube through the housing 14. Each blade has at the circumference of the wheel hub 22 a substantially straight radially extending portion root 30 from which extends outwardly an arcuately curved portion 31 formed on the respective radii R1 and R2, the outer edge 3l' of which is beveled and extends in advance of the root portion 3d, in the direction of rotation of the wheel 2i, so that as will be readily understood from FIG. 3, the blades may cut into the water in the tube 25 and force the same rearwardly with a minimum of resistance, both downwardly and rearwardly.

It has also been found that this configuration of the blades results in substantially all of the water engaged thereby being forced rearwardly through the tube 25, and substantially no water being carried by the blades about the hub 22 and through the housing 14, so that no power-wasting, inefficient pumping action is involved. This may be due partly to the considerable centrifugal forces resulting from the fact that the turbine wheel 21 may be rotated at relatively high speed, of the order of 3000 rpm., with a speed of at least 3500 r.p.m. being contemplated by the invention, thus offsetting any tendency to carry water around the device. Although the exact proportions and curvature of the blades in cross section may of course be varied, in general the straight root portion Sti is approximately one-fourth of the total radial extent of the blade 23, the curved portion 31 extending for substantially three-fourths of the height or radial extent of the blade. Thus through a combination of the particular blade form and the relatively high speed at which the turbine wheel 21 is driven, the blades 23 rotating into and out of the tube 25 develop a jet of great force and speed therein which by reason of its rearward direction drives the boat forward by reaction therewith.

It will be apparent that the jet passes from the rear end of the tube 2S into the tube 26 and issues ultimately from the rear end of tube 26. Means are provided in the tube 26 to control the movement of the hull H, in the form of vanes arranged rotatably therein. A reversing vane 33 shaped and dimensioned to have a slight clearance in the interior of the tube 26 when disposed transversely thereof is mounted in the tube 26 for rotation about a vertical axis. This rotational axis of the reversing vane 33 is spaced rearwardly from the rear end of the tube 25, a distance somewhat greater than half the width of the tube 26, so that when the vane 33 is arranged extending axially of tube 26 it will clear the tube 25. The rotatable mounting of the reversing vane is accomplished by means of a shaft 3d which extends vertically through the center of tube 26 and projects outwardly of the base plate it) any suitable distance. The shaft 34 is journaled in the lower wall of the tube 26, and may also be journaled in the base plate 1? if desired, although this is rendered unnecessary by a tubular housing 35 through which the shaft 34 extends and in which it has suitable bearing, the housing 35 being welded as at 36 to the outer face of the base plate itl. An opening 37 may be formed in the bottom B of the boat to accommodate the shaft and housing, which as will be apparent, extend into the interior of the hull. The shaft 34 preferably extends upwardly to a height such that the housing 35 may extend to a height above the level of the water in which the boat is operated, so as to avoid the possibility of water coming into the boat interior through the housing. If desired, of course, the housing may be of less height and provided with suitable sealing means to prevent passage of water therethrough about the shaft. Similarly, suitable anti-friction bearings may be provided for the shaft 34, in place of the bearing arrangement illustrated. The reversing vane 33 is fixed on the lower portion of the shaft 34 in any suitable manner or by any suitable means, not shown.

At the rear of the tube 26 there is mounted for rotation about a vertical axis the deflecting or steering vane 38 which is suitably fixed on a vertically extending shaft 39 similar to the shaft 34 and having a similar bearing arrangement which may include the housing 4) receiving the shaft 39 therethrough and secured to the upper face of the base plate itl in any suitable manner, as by a weld 41. The housing 40 and weld il are similar to the housing 35 and weld 36 in the case of the shaft 34, and an aperture 42 may be formed in the bottom of the boat to allow the shaft 39 and housinty 46 to extend upwardly into the interior of the hull. The side walls of the tube 25 are cut away or otherwise formed so as to terminate forwardly of the bottom wall thereof, as indicated at 43, and the bottom wall is cut away at each side at an angle of substantially forty-five degrees from the rear end of the side wall to the central portion of the bottom, as indicated at 44, and provided with an apexial portion 45 for mounting the shaft 39. The vane 38 is of a height somewhat less than that of the interior of the tube 26, so as to have sufficient clearance therein for free turning, and may be of any suitable length. The portion of the vane 38 extending forwardly from the shaft 39 preferably is of such length as to engage against one or the other of the side envase? walls of the tube 2'6adjacent the cut-away rear'end portion 43 thereof to limit the rotation of the vane in either direction. It will be appreciated that the amount of turning allowed the vane 38 in eitherdirection may be greater than the approxmatelyforty-ve degree rotation from the center position thereof which is possible with the construction illustrated, without any departure from the invention. Both of the vanes 33 and 33 may be of suitably streamlined form so as to oiferaminimum resistance to passage of the jet through the tube 26 when they are disposed in their centered positions,`that is parallel to the sides of the tubes.

Fixed on the upper end of the shaft 34 is -a radially extending turning arm 45 by means of which the shaft and reversing vane`33 may be rotated, so that the vane 33 may be turned from a central position extending parallel 4to the sides of the tube y26 to one extending transversely thereof and blocking the tube, these two positions of the yane -being'illustrated in FIG. 5 in full lines and dotted lines, respectively. The .arm 45 may be `formed with a suitable handle for direct manual operation thereof, or may be connected to any suitable linkage for operation from a distance. VIn the event more than one apparatus 4according to the `present invention is employed, as illus- Vtrated in FIG. 1, the arms 45 of the several reversing vane shafts 34 may be connected by a link or links 46 so lthat they may be moved simultaneously and in correspond- 'e'nce with each other. One of the shafts 34 may have xe'd thereon, in addition to the arm 45, a rigid arm 47 to ythe free end of which may be connected a control rod 4S `or thelike extending to a point forward of the propulsion apparatus so that from such point the rod may be shifted forwardly or rearwardly to swing the arm 47 in one direction or the other and thus -turn the several shafts 34 fthrough the linkage described so as to .position the several reversing vanes 33 in the desired relation to the respective tubes 26. In any case, suitable locking means, "not shown, may be provided to hold the arm 45 `of each shaft 34 in a predetermined position corresponding to a selected position of the associated reversing vane 33.

On the upper end of the shaft 39 is xed a radially extending tiller arm 5t) by means of which the associated steering vane38 may be turned to one side or the other vfrom its central or straight ahead position, and means 'may be employed to hold the tiller arm in a selected adjusted position thereof, if desired, such means not forming a part of the present invention and therefore not being illustrated. When two or more of the apparatus of thevinvention are employed as illustrated in FIG. l, the

several tillerarrns may belinked together for operation simultaneously andco'rre'spondingly so that all of the deflecting or steering vanes'38 will extend at the same angle relative to the several tubes 26. For this purpose, a link 51 is provided extending between the ends of the tiller arms and pivotally `'connected to each thereof. If it be desired to operate the steering vanes from a remote point, such as the cockpit or other location forward of the propulsion apparatus, each end of the link S1 may have a cable 52 secured `thereto and extending forwardly, as to a conventional steering wheel, after passing through a pulley 53 `secured to the interior of the hull at la point generally in line with the link 51. As is obvious, by pulling on one of the cables 52 while allowing the other to run, the tiller arms 50 may beswung to one side or the other'to position the Asteering vanes 38 in a desired position.

A somewhat different embodiment of the invention is illustrated in FIGS. 6 to 8, inclusive, in which parts substantially identical tothose disclosed in FIGS. 1 to 5, inelusive, are designated by the same reference characters. The construction of the parts of the apparatus mounted on the upper face of the base plate 10 is substantially the same as that of the correspondin-g parts of the iirstdescribed embodiment, comprising the housing 14 with the turbine wheel 21 rotatably mounted therein on the shaft 2t) 4and havingthe blades 23 of the form andconstruction described, and the shafts 34 and 39 extending through the vertical housings 35 and 40 secured to the pla-te 10 by welds 36 and 41, the apertures 12, 37 and 42 being provided in the bottom B of the hull H as already described to accommodate the parts secured on the upper face of the base plate. As in the case of the embodiment of FIGS. l to 5, the plate 10 is shown as secured to the boat bottom B by a weld 10', although the securement may be any other appropriate means. The means for driving the turbine wheel 21 and the means for operating the shafts 34 and 39 to control the vanes 33 and 33 may be substantially the same as in the first-described embodiment.

In the embodiment of FIGS. 6 to 8, inclusive, the tubular structure which in the rst-mentioned embodiment comprised the two tubes 25 and 26 takes the form of a single tube 60 extending longitudinally along the hull and defined by a suitable member of channel section having its free edges secured to the lower face of the base plate 10 as by welds 61. The tube 6i) is of substantially identical cross section with the tube 25 previously described, having forward intake openings 60' therein corresponding tothe openings 27' in the tube 26, so as to have the same cooperative relation with the turbine wheel 21 as the tube 25, but is of considerably greater length than the tube 25 so that it may also provide for the same cooperative relationship with the vanes 33 and 38 as the tube 26. To the rear of the aperture 11 in the base plate, or rearwardly-of the blades 23 which rotate through the tube 66, and forwardly of the axis of rotation of the reversing vane 33, the side walls of the tube 60 are provided with apertures 62 which serve as passage means correspondingtto the passage 27 of the previously described embodiment. v As has already been indicated, the reversing and steering vanes 33 and 38 are mounted in the tube 60 in substantially the same manner as in the case of the tube V26. The side walls of the tube 60 terminate in a vertical plane forward of the rear end of Vthe bottom wall, as in the case of the side walls of the tube 26 as previously explained, the rear ends of the side walls being indicated at 63 in FIGS. 6 and 7. The rear end of the bottom wall of the tube 6@ is formed substantially like that of the bottom wall of the tube 26, being cut away at each side at an angle of substantially forty-tive degrees from the side wall ends 63 toward the center of the bottom wall and `having a central apexial portion64 similar to the po-rtion 45 and similarly serving for mounting the shaft 39. The bottom wall of the tube 60, shown in section in FIG. 6, is indicated in phantom in FIG. 7. From FIG. 7 there are also apparent the two extreme positions of the steering vane 33, determined by engagement of the forward end of the vane with one side wall orthe other adjacent the rear end 63 thereofas explained Vin connection with the embodiment of FIGS. l to 5. One of these positions is shown in FIG. 7 in dotted lines and the other in dot-dash lines, the full line position of the vane 38 being the normal or central position thereof. As in the case of the previously described embodiment, the maximum of movement of the steering Avane 38 to either side from its central position may be greater than the fortyfive degrees permitted by the construction described, if desired.

It will be apparent that `with either embodiment, the turbine Wheel and housing, the shafthousings 35 and 40, and the tube-dening members maybe welded or otherwise secured to Vthe base plate 16, and the vanes 33 and 38 together with the respective shafts 34 and 39 may be properly assembled therewith, and the base plate with the several elements secured and mounted thereon then applied to the boat bottom B as a unit, the wheel housing 14 being inserted through the aperture 12, and the shaft and housing constructions extending through the apertures 37 and 42 after securement of the base plate .10 -to the bottom of the boat, the arms 45 and 56 being then secured on the respective shafts 34 and 39. It will also be evident that if desired the aperture l2 in the bottom of the boat hull may be expanded to a size such as to include the apertures 37 and i2 and only slightly less than the base plate lo, and the base plate l@ employed as a closure for such enlarged opening, in effect replacing a portion of the bottom B. in such case, it will be evident .hat the entire propulsion apparatus may be preassernbled on the oase plate l@ as a unit, including the arms on the shafts 34 and 39, and the entire assembly applied as a unit to the boat, the several elements which extend into the interior of the hull being inserted through the enlarged opening as the plate iii is brought to position closing such opening. If a plurality of the propulsion apparatus are to be employed with a common shaft 20, as shown in FIG. l, the various elements associated with each base plate Il@ may be assembled therewith, with the common shaft 2G extending through the several turbine wheel housings if; and the wheels 2l secured thereon, and the plurality of units or assemblies applied to the boat at substantially the same time, by providing a transverse slot or aperture extending between the apertures 12 so as to accommodate the shaft 2@ and allow its insertion in the assembled condition into the interior of the hull. Such transverse opening or slot may be closed by a suitable plate substantially in the same manner as the apertures l2 are closed by the base plates liti. Thus, the entire propulsion apparatus, or substantially the entire apparatus, may be assembled, transported, handled and applied to a boat hull as a unit, so that the purchaser or user o-f the apparatus is subjected to a minimum of expense and labor in the installation thereof in a hull.

In operation of the apparatus after the installation in a hull, the engine E is started to drive the turbine wheel 21 through the belt B and shaft 2t), the reversing vane 33 being in its central position, or in other words parallel to the sides of the tube construction, and the boat may immediately begin moving, even though the wheel has not reached the desired speed which results in the development of a jet through the tube construction for reactive driving of the boat. At the low starting speed and while the high speed is being'reached, the wheel 21 may have a small, but relatively negligible paddle wheel action, moving the boat at least in part by reaction of the blades with the water. However, the driving speed soon reaches a point wherein the jet shoots rearwardly through the tube construction, past the vanes 33 and 3S to issue from the rear of the tube, providing a powerful reactive thrust which allows the boat to move at high speed. The direction or course of the boat is determined by the position of the steering vane 33, which when in its centered or normal position allows the jet to pass out of the associated tube directly in line with the tube and with the plane of the turbine wheel, so that the boat is moved directly forward. By turning the vane to one Side or the other, the jet is deflected or diverted thereby, and by its impingement on the vane causes the boat to turn, as will be obvious.

The reversing vane 33 when rotated from its central or longitudinal position to a position transverse of the associated tube, blocks the passage of the jet rearwardly therethrough, detiecting it forwardly to pass out of the tube construction through the passage means 27 or 62. The forward direction thus imparted to the jet results in the boat being moved rearwardly, as will be evident, instead of forwardly. The deflecting or steering vane 38 may be employed to steering the boat in its rearward movement, although in this case the steering vane reacts with the water in which the boat is operating tot achieve a determination of the course, instead of reacting with the jet issuing from the rear of the tube.

It will be seen that the essential difference between the two embodiments of the invention illustrated resides in the form taken by the passage means for forward issuance of the jet from the tube construction upon movement of the reversing vane to its blocking or reversing position. This arrangement, however, has the advantage that it permits easier rotation of the vanes 33 and 38 because the turning thereof is not hindered by as strong a jet as would otherwise be the case. In the second-described embodiment, the tube construction, comprising the single tube 60, is of substantially the same cross-sectional area throughout its length and the jet developed by the turbine wheel 21 retains substantially the same thrust throughout, and thus provides a maximum of power for driving the boat. At the same time, since the cross-sectional area of the tube construction in which the vanes 33 and 38 are mounted is smaller in the case of the tube 60 than in that of the tube 25, the areas of the vanes exposed to the jet are similarly smaller so as to minimize as far as possible any diiiiculty in turning the vanes which may arise from the force of the jet acting thereon.

it will be evident that when a plurality of the propulsion mechanisms of this invention are employed together to drive a single craft, the arrangement for linking the several vanes 33 together for simultaneous and corresponding rotation, and the arrangement for similarly swinging the several steering vanes 38 as one, provide for maximum eiciency in that there is no counteraction as between the respective vanes.

The vane 33 may be employed not only for reversing the direction of movement of the boat hull, but for effecting a neutralization of the jet so that it does not tend to drive the boat in either direction, even though the turbine wheel 21 is rotated at its effective driving speed. This is accomplished by rotating the vane 33 to a position in which it in effect divides the jet into two portions, one of which moves rearwardly through the tube construction and out the rear end thereof so as to tend to impart a forward movement of the boat, while another part is yblocked and deflected to flow forwardly out of the tube construction through the passage means as previously described, this forward-flowing portion tending to move the boat rearwardly. The two oppositely acting portions 0f the jet thus neutralize each other, and the boat is thus not under way or driven in either direction.

It will readily be evident from the previous explanation of the operation of the reversing vane 33 in effecting reverse or rearward movement of the boat, and also in neutralizing any driving thereof in either direction, that the vane 33 may be employed to control the speed of the boat in either forward or rearward movement thereof by turning the vane 33 to a position somewhat similar to that employed for the neutralization of the jet, but dividing the jet into unequal portions, as that a rearwardly directed portion provides more force than the forwardly directed portion, with the result that the boat moves forwardly at a speed corresponding to the differential between the opposing forces of the divided jet. Similarly, if the forwardly directed portion of the jet exceeds the force of the rearwardly directed jet portion, the boat will move rearwardly. The ability to employ the vane 33 for controlling the speed of the boat in either direction, without necessitating a change in the speed of the engine E or of the rotation of the turbine wheel 21, is of great advantage in providing great exibility in the operation of the craft, since it permits temporary slowing of the boat without having to adjust the motor to slow speed and then bring it to full speed again.

It will beapparent that by reason of the reversing vane 33 a very elfective and smooth control of the boat, from forward at full speed through smoothly decreasing slower speeds, to a neutral or idling position, and on to a reverse movement with varying speeds, is achieved without gears or other relatively complicated means. As already mentioned, reversing of the boat so that it will move backward is accomplished without any requirement for reversing the direction of the driving engine or the turbine wheel, and such reversal is accomplished smoothly and quietly, and without any appreciable shock to the boat or its parts. Obviously, the reversing vane will effect quick stopping of the boat. The deflecting or steering vane provides for quick and positive steering response of the boat in either direction of its movement, since the vane will react with -the jet for steering the boat in forward movement, and with the water in which the boat is operating when Ithe boat is moving rearwardly. The propulsion apparatus of this invention allows operation of boats and larger craft in shallow waters, since the tubular structure defined on the bottom of a small boat extends downwardly only a few inches, some three or four inches in most cases. In Ithis connection, it may be pointed out that if desired the tubular construction may be provided above the plane of the bottom of the boat, in the form of a tunnel or vthe like, and thus the projection below the bottom of the boat m-ay be eliminated entirely. It will be noted that there is no propeller or other similar exposed rotating part, the only rotating part of the propulsion mechanism being the turbine -wheel and its shaft, the wheel being completely enclosed in the housing and the tube construction, and the shaft being encased or housed along with the `drive belt and the rotating pulleys therefor, as already mentioned. The apparatus, therefore, is particularly safe when operating in water where swimmers, skiers, or divers :are pursuing their sport. It will |be apparent that the developed thrust is distributed over a relatively large area of the boat bottom, thus avoiding concentration of stress -at any particular point and eliminating the danger of failure of critical parts. 'Ihe turbine wheel provides for a very high efficiency in the operation of the boat, since no power is lost or dissipated in pumping water, that is carrying it through the wheel housing, and substantially all of the power is employed in developing the jet which provides the driving force. The propulsion apparatus of this invention readily lends itself to installation at the stern of a boat, thus providing more usable and available space within the hull, and lat the same time allowing considerably less bottom bracing of the hull to be employed than would otherwise be the case. Such bracing, at the stern at least, may in large part take the form of the base plate by which the apparatus is mounted.

Having -thus described my invention, it will be obvious that various modifications may be made in the same without departing from the spirit of the invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

What I claim as new and desire to secure by Letters Patent is:

1. A marine propulsion apparatus comprising a first substantially straight tube extending longitudinally of a boat hull exteriorly thereof below water level and open at both ends, an opening from the hull interior into said first tube, a turbine wheel rotatably mounted adjacent said opening to have the blades thereof extend through the opening into the first tube to develop therein upon rotation of the wheel a jet directed rearwardly of the hull to effect forward movement of the hull, means for rotating said turbine wheel at sufficient speed to develop said jet, a second tube substantially aligned with and of greater cross sectional area than said first tube and disposed with its forward portion in overlapping relation with the rear portion of the first tube, and intercepting means in said second tube rearwardly of the first tube movable progressively between a position allowing full jet flow through the second tube and a position substantially preventing fiow therethrough, said overlappingly related tube portions defining a passage for forward ow from the second tube of any jet portion prevented from rearward ow therethrough.

2. A marine propulsion apparatus as defined in claim 1, including rudder means at the rear of the second tube operable in forward movement to react with the iet and in rearward mo-vement to react with the water supporting said hull for determining the Acourse of the hull.

3. A marine pro-pulsion apparatus comprising a first substantially straight tube extending longitudinally of a boat hull exteriorly thereof below water level and open at both ends, an opening from the hull interior into said firs-t tube, a turbine wheel rotatably mounted adjacent said opening to have the blades thereof extend through the opening into the first tube to develop therein upon rotation yof the turbine wheel a jet directed rearwardly of the hull for effecting -forward movement of the hull, means for rotating said tur-bine wheel at sufficient speed to develop said jet, a second tube substantially aligned with and of greater cross-sectional area than said first tube and disposed with its forward portion in overlapping relation with the rear portion of .the first tube and rudder means at the rear of the second tube operable in forward movement to react with the jet and in rearward movement to react with the water supporting said hull to determine the course of the hull.

4. A marine propulsion apparatus comprising a high speed turbine wheel having a central drum portion and a plurality of radially extending turbine blades, each of which has a straight radially extending root portion and a radial outer portion extending outwardly from said root portion and has arcuately curved faces formed on different axes of generation, the radii of curvature of said outer blade faces being approximately three times the radial extent of the root portion, a housing structure enclosing the upper portion of said turbine wheel including said drum portion and constructed to dispose the latter substantially within a hull on which the apparatus is to be mounted, said housing including a bottom portion constructed to be disposed below the bottom of such a hull with the turbine blades extending downwardly below such a bottom, said bottom portion of the housing structure extending below and rearwardly of the depending turbine blades and forming a channel for the passage of water rearwardly discharged from said turbine wheel, said bottom portion having means forming a passageway disposed below and communicating at its rear end with said channel for the passage of water through said passageway in a forward direction, and a control member cooperable relative to said channel and said passageway for controlling the flow of water through the latter, said bottom housing portion being open at its forward end and at opposite sides of the turbine blades to provide substantially unrestricted water flow operatively into the path of said turbine blades, with all water entering said bottom portion being directed rearwardly through said channel without any water carrying over around said wheel.

References Cited in the file of this patent UNITED STATES PATENTS 115,425 `Boyman May 30, 1871 133,275 Wells Nov. 19, 1872 164,033 Pratt June 1, 1875 340,237 Nagel et al. Apr. 20, 1886 1,365,939 Mortensen Jan. 18, 1921 1,374,533 Stenberg Apr. 12, 1921 1,498,919 Jensen June 24, 1924 1,542,540 Zsiki June 16, 1925 1,572,812 Rees Feb. 9, 1926 2,042,499 Brady n- June 2, 1936 FOREIGN PATENTS 346,099 Germany .r Dec. 24, 1921 457,650 Great Britain Dec. 2, 1936 65,371 Norway June 7, 1943 523,021 Italy Apr. 13, 1955 

1. A MARINE PROPULSION APPARATUS COMPRISING A FIRST SUBSTANTIALLY STRAIGHT TUBE EXTENDING LONGITUDINALLY OF A BOAT HULL EXTERIORLY THEREOF BELOW WATER LEVEL AND OPEN AT BOTH ENDS, AN OPENING FROM THE HULL INTERIOR INTO SAID FIRST TUBE, A TURBINE WHEEL ROTATABLY MOUNTED ADJACENT SAID OPENING TO HAVE THE BLADES THEREOF EXTEND THROUGH THE OPENING INTO THE FIRST TUBE TO DEVELOP THEREIN UPON ROTATION OF THE WHEEL A JET DIRECTED REARWARDLY OF THE HULL TO EFFECT FORWARD MOVEMENT OF THE HULL, MEANS FOR ROTATING SAID TURBINE WHEEL AT SUFFICIENT SPEED TO DEVELOP SAID JET, A SECOND TUBE SUBSTANTIALLY ALIGNED WITH AND OF GREATER CROSS SECTIONAL AREA THAN SAID FIRST TUBE AND DISPOSED WITH ITS FORWARD PORTION IN OVERLAPPING RELATION WITH THE REAR PORTION OF THE FIRST TUBE, AND INTERCEPTING MEANS IN SAID SECOND TUBE REARWARDLY OF THE FIRST TUBE MOVABLE PROGRESSIVELY BETWEEN A POSITION ALLOWING FULL JET FLOW THROUGH THE SECOND TUBE AND A POSITION SUBSTANTIALLY PREVENTING FLOW THERETHROUGH, SAID OVERLAPPINGLY RELATED TUBE PORTIONS DEFINING A PASSAGE FOR FORWARD FLOW FROM THE SECOND TUBE OF ANY JET PORTION PREVENTED FROM REARWARD FLOW THERETHROUGH. 